WndProc, how to catch all buttons press?

I am developing an application for a .NET CF3.5 WM6.1 device with a barcode reader and want to catch all buttons (F1, 1, scanner buttons) click on a device. Especially I am interested how to catch barcode button press. I wrote a tiny app, but the only action I can catch is form close. Could anyone help me with this code? What I missed?

public partial class Form1 : Form
{
    MsgHandler m_MsgHandler;
    public Form1()
    {
        InitializeComponent();
        m_MsgHandler = new MsgHandler(this);
    }
    public class MsgHandler : MessageWindow
    {
        public const int WM_CLOSE = 71;
        public const int WM_USER = 0x0400;
        public const int WM_SCANTRIGGER = WM_USER + 702;
        private Form1 m_myForm;

        public MsgHandler(Form1 form)
        {
            m_myForm = form;
        }
        protected override void WndProc(ref Message msg)
        {
            switch (msg.Msg)
            {
                case WM_SCANTRIGGER:
                   this.m_myForm.DoAction1();
                   break;
               开发者_如何学Python case WM_CLOSE:
                   break;
                default:
                    this.m_myForm.DoAction2(msg.WParam.ToInt32());
                    break;
            }
        }
    }
    public void DoAction1()
    {
        MessageBox.Show("Scann btn pressed!");
    }
    public void DoAction2(int button)
    {
        MessageBox.Show(button.ToString());
    }
}

Thank you, Lukas

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Barcode reader usually behave like normal keyboard so there is no special buttons pressed. You just get messages that keys got pressed and after whole code you get enter.

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Microsoft POS for .NET may be helpful.